"Pistachio Blaster" Listens for Perfect
Nuts

Shells of perfectly ripened pistachios split open naturally, revealing
a rich-tasting, lime-green kernel that's ready to roast and enjoy. Nicknamed
"laughing pistachios" because they look like they're smiling at you, open-shell
nuts typically make up about 78 percent of the U.S.-grown harvest.

The Blaster is designed to reduce losses otherwise caused when sorting
machines make errors, misdirecting premium, open-shell pistachios into bins of
closed-shell nuts. Performing at the respectable speed of about 25 nuts per
second, the Blaster doesn't damage nuts and can pay for itself in less than a
year.

In a sequence of steps that occur faster than the blink of an eye, the
Blaster analyzes sounds made during and immediately after each nut strikes a
polished stainless steel block. Those sounds, first captured as electrical
signals by a precisely positioned directional microphone, are sped to a
personal computer, where they're converted into digital data--some 350 pieces
of information, or data points, for each nut.

The computer distinguishes the distinctive sound pattern made by the
impact of a closed-shell pistachio from that of an open-shell nut. When this
analysis reveals the telltale sounds of a closed-shell nut's bounce, the
computer sends a signal that causes a blast of compressed air to direct the nut
to the reject bin.

One of the nation's largest pistachio processors,
Setton Pistachio of Terra Bella,
Calif., holds a license for the patented Blaster and is already using several
of these novel machines.

Read more
about the research in the November issue of Agricultural Research
magazine.